Most vehicles in operation today (and many other devices) are powered by internal combustion (IC) engines. Internal combustion engines typically have a plurality of cylinders or other working chambers where combustion occurs. Under normal driving conditions, the torque generated by an internal combustion engine needs to vary over a wide range in order to meet the operational demands of the driver. Over the years, a number of methods of controlling internal combustion engine torque have been proposed and utilized. Some such approaches contemplate varying the effective displacement of the engine. One such approach is often referred to as “skip fire” engine control. Skip fire engine control contemplates selectively skipping the firing of certain cylinders during selected firing opportunities. Thus, for example, a particular cylinder may be fired during one firing opportunity and then may be skipped during the next firing opportunity and then selectively skipped or fired during the next. This is contrasted with conventional variable displacement engine operation in which a fixed set of the cylinders are deactivated during certain low-load operating conditions. In general, skip fire engine control is understood to offer a number of potential advantages, including the potential of significantly improved fuel economy in many applications.
A stereotype associated with skip fire engine control is that skip fire operation of an engine will make the engine run significantly rougher than conventional operation. In many applications such as automotive applications, one of the most significant challenges presented by skip fire engine control is vibration management. The present application describes techniques that utilize torque converter clutch slip (and/or the slip of another drive train component) to mitigate vibration during skip fire operation of an engine.